#!/usr/bin/python
#
#  Utility to dump bytecode into a human readable form.
#

import os
import sys
import struct
import optparse

def decode_string(buf, off):
	strlen, = struct.unpack('>L', buf[off:off+4])
	off += 4
	strdata = buf[off:off+strlen]
	off += strlen

	return off, strdata

def sanitize_string(val):
	# Don't try to UTF-8 decode, just escape non-printable ASCII.
	def f(c):
		if ord(c) < 0x20 or ord(c) > 0x7e or c in '\'"':
			return '\\x%02x' % ord(c)
		else:
			return c
	return "'" + ''.join(map(f, val)) + "'"

def decode_sanitize_string(buf, off):
	off, val = decode_string(buf, off)
	return off, sanitize_string(val)

def dump_function(buf, off, ind):
	count_inst, count_const, count_funcs = struct.unpack('>LLL', buf[off:off+12])
	off += 12
	print '%sInstructions: %d' % (ind, count_inst)
	print '%sConstants: %d' % (ind, count_const)
	print '%sInner functions: %d' % (ind, count_funcs)

	nregs, nargs, start_line, end_line = struct.unpack('>HHLL', buf[off:off+12])
	off += 12
	print '%sNregs: %d' % (ind, nregs)
	print '%sNargs: %d' % (ind, nargs)
	print '%sStart line number: %d' % (ind, start_line)
	print '%sEnd line number: %d' % (ind, end_line)

	compfunc_flags, = struct.unpack('>L', buf[off:off+4])
	off += 4
	print '%sduk_hcompiledfunction flags: 0x%08x' % (ind, compfunc_flags)

	for i in xrange(count_inst):
		ins, = struct.unpack('>L', buf[off:off+4])
		off += 4
		print '%s  %06d: %08lx' % (ind, i, ins)

	print '%sConstants:' % ind
	for i in xrange(count_const):
		const_type, = struct.unpack('B', buf[off:off+1])
		off += 1

		if const_type == 0x00:
			off, strdata = decode_sanitize_string(buf, off)
			print '%s  %06d: %s' % (ind, i, strdata)
		elif const_type == 0x01:
			num, = struct.unpack('>d', buf[off:off+8])
			off += 8
			print '%s  %06d: %f' % (ind, i, num)
		else:
			raise Exception('invalid constant type: %d' % const_type)

	for i in xrange(count_funcs):
		print '%sInner function %d:' % (ind, i)
		off = dump_function(buf, off, ind + '  ')

	val, = struct.unpack('>L', buf[off:off+4])
	off += 4
	print '%s.length: %d' % (ind, val)
	off, val = decode_sanitize_string(buf, off)
	print '%s.name: %s' % (ind, val)
	off, val = decode_sanitize_string(buf, off)
	print '%s.fileName: %s' % (ind, val)
	off, val = decode_string(buf, off)  # actually a buffer
	print '%s._Pc2line: %s' % (ind, val.encode('hex'))

	while True:
		off, name = decode_string(buf, off)
		if name == '':
			break
		name = sanitize_string(name)
		val, = struct.unpack('>L', buf[off:off+4])
		off += 4
		print '%s_Varmap[%s] = %d' % (ind, name, val)

	idx = 0
	while True:
		off, name = decode_string(buf, off)
		if name == '':
			break
		name = sanitize_string(name)
		print '%s_Formals[%d] = %s' % (ind, idx, name)
		idx += 1

	return off

def dump_bytecode(buf, off, ind):
	sig, ver = struct.unpack('BB', buf[off:off+2])
	off += 2
	if sig != 0xff:
		raise Exception('invalid signature byte: %d' % sig)
	if ver != 0x00:
		raise Exception('unsupported bytecode version: %d' % ver)
	print '%sBytecode version: 0x%02x' % (ind, ver)

	off = dump_function(buf, off, ind + '  ')

	return off

def main():
	parser = optparse.OptionParser()
	parser.add_option('--hex-decode', dest='hex_decode', default=False, action='store_true', help='Input file is ASCII hex encoded, decode before dump')
	(opts, args) = parser.parse_args()

	with open(args[0], 'rb') as f:
		d = f.read()
		if opts.hex_decode:
			d = d.strip()
			d = d.decode('hex')
	dump_bytecode(d, 0, '')

if __name__ == '__main__':
	main()
